Wind turbine generators may comprise partial and full load controllers for determining pitch and power references for the pitch actuators and the power generator, respectively. The objective for the partial load controller, which is selected for wind speed below a rated wind speed, is to optimise power production from a given available amount of wind energy. The objective for the full load controller, which is selected for wind speed above the rated wind speed, is to produce the nominal power of the wind turbine generator.
Switching between the partial and full load controllers is required as the wind velocity changes between wind velocities below and above the rated wind speed. Such switching may have undesirable effects on structural loads, utilisation of the wind energy and other operating conditions of the wind turbine generator.
Thus, it is a problem that known control schemes of wind turbines may have difficulties in dealing with switching between different control schemes.